1. Field of the Invention
This invention relates to a leakage prevention system, to be used in combination with liquid storage and transportation tanks such as those used in tankers and oil trucks, adapted to be flexible, liquid impervious and completely puncture resistant, and be securely fastened to the upper surface of the tank in a manner which permits the utilization of overflow redistribution and containment means attached at a flanged aperture.
2. Description of the Related Art
In the modern battle between industrial advancement and environmental consciousness, there is a pressing need for a safe and efficient means of transporting environmentally harmful, yet industrially vital resources such as crude oil. The most effective means for transporting such resources has proven to be large tankers or oil trucks, but these means are not environmentally secure and can result in disastrous spills. As a result, a means for further securing the puncture prone tanks commonly utilized is needed.
Among the method utilized to attempt to secure tanks from puncture is that of installing a double bulkhead between the exterior of the transporting vessel and the holding tank. This method, which is the most commonly used, only protects against shallow punctures because the inner bulkhead is no more puncture resistant that the outer bulkhead, and is there merely as a secondary restraint source. Further, the dual bulkhead protection method is industrially inefficient because it substantially reduces the volume that may be carried by the vessel, and requires that existing vessels wanting to install the dual bulkhead be removed from service for extended periods of time.
Other smaller scale methods of securing gas tanks, such as in the patent to Boschi, et al., U.S. Pat. No. 3,426,937 and Suter, U.S. Pat. No. 3,622,035, are also ineffective for providing a reliable securing method for use in combination with large liquid storage and transportation tanks. The patent to Boschi, et al. discloses an impact resistant tank containing a flexible inner liner, which while providing a means for securing the tank from a displaced impact, does not provide any protection from concentrated punctures that would poke through the flexible liner. The patent to Suter discloses a vehicle puncture resistant fuel container adapted to be lightweight, and provide added puncture protection in particularly vulnerable and puncture prone areas of the fuel tank. The container discloses a flexible fuel cell disposed within a rigid supporting structure, and woven puncture resistant pads or maps which are placed on the exterior of the rigid supporting structure in accordance with known, vulnerable areas of the fuel tank. The puncture resistant patches of Suter are not intended to provide protection for the entire tank, but are only intended as a means to guard certain areas from relatively low force punctures that could still pass through the necessarily lightweight rigid supporting structure. Further, the fuel container in Suter does not provide a means for containing and redistributing overflow that would result from the compression of the flexible fuel cell during impact. These smaller scale protection methods do not relieve the need for a leakage prevention method capable of protecting against sharp, forceful impacts, and when necessary, redistributing and containing overflow that may result when storage and transportation tanks, which necessarily contain a maximum volume, are subjected to impact which compresses the tank. Further, they provide no remedy for existing tanks that did not have such a container installed during their initial building.
Applicant's invention does address all these needs. Applicant's leakage prevention system provides a method directed to withstand punctures from forceful impact such as those capable of rupturing the hull of a tanker. The invention provides a method that will be industrially acceptable in that very little of the storage and transportation tank's capacity will be removed, and, since the installation does not require restructuring of existing tanks and may be easily installed in existing tanks, the down time while the vessel is refitted will be minimal. Applicant's invention is also environmentally beneficial in that, in addition to providing a puncture resistant shell that will prevent leakage at the point of impact, it also provides a means of safely containing and redistributing overflow that will necessarily result when an impact occurs.